In response to the uncertainties and time-varying disturbances in the dynamic model of the 6-PSS parallel motion simulator,a robust control strategy based on sliding mode variable structure was proposed.Firstly,the dynamic model of the mechanism was established using the principle of virtual work.The dynamic model indicated that the 6-PSS parallel mechanism was a multivariable system with nonlinear and strongly coupled characteristics.The dynamic model was processed offline to reflect the actual dynamic characteristics of the mechanism and meet the real-time computational requirements of the device.Then,based on the simplified dynamic model,a global fast terminal sliding mode controller(GFTSMC)was designed.The Lyapunov function was employed to analyze the control law,demonstrating the stability of the controller.Finally,the control strategy was applied to the trajectory tracking control of the 6-PSS parallel motion simulator and compared with PD feedforward control and traditional sliding mode control(SMC)through experimental comparison.The research results indicate that,comparing to PD and SMC,GFTSMC reduces the average error by 82.92%and 18.88%respectively,and the standard deviation by 80.03%and 41.73%respectively.Moreover,it is capable of suppressing oscillations,making it an effective and practical robust control scheme for the 6-PSS parallel motion simulator.The research results can provide a theoretical basis for the control and engineering application of the 6-PSS parallel motion simulator.
关键词
并联机构/动力学建模/虚功原理/滑模控制/李雅普诺夫函数/全局快速终端滑模控制器
Key words
parallel mechanism/dynamic modeling/virtual work principle/sliding mode control/Lyapunov function/global fast terminal sliding mode controller(GFTSMC)
维普
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